Effects of different autotoxins on antioxidant enzymes and chemical compounds in tea (<i>Camellia sinensis</i> L.) Kuntze

Abstract

Continuous cropping obstacle is a serious problem in tea (Camellia sinensis L.) planting. In order to understand the mechanism of this phenomenon, SOD, POD, CAT and MDA in the roots of tea tree and chemical compounds in leaf of tea were analyzed. The results showed that the autotoxins had both inhibitory and stimulatory effects on antioxidant activities, stimulatory effects increased with time at low concentration, but the inhibition increased with the increasing of growing years. The antioxidant enzyme activities increased first but decreased then, with the peak value differed in different treatments. The autotoxins also increased the MDA contents, while decreased the contents of Chl-a, Chl-b, carotenoids and water extracts in the fresh tea leaves. Results indicated that the activities of SOD, CAT and POD depended on autotoxins; their time of action and concentration and various physiological processes of tea tree were inhibited due to the contents of Chl-a and Chl-b decreased. These results suggested the adverse effects of autotoxins on the enzymes of antioxidant defense system resulting in lipid peroxidation in roots of tea seedlings and the autotoxins could impact tea yield and quality.

Key words: Camellia sinensis L., autotoxicity, autotoxins, peroxidase, catalase, superoxide dismutase, malondialdehyde, chemical compounds.